Flame retardant composition comprising a phosphonic acid metal salt and a nitrogen containing compound

ABSTRACT

Flame retardants are described, comprising (A) at least one metal or metalloid salt of a phosphonic acid of formula (I) wherein R is hydrogen, C 1 -C 18 alkyl, C 5 -C 6 cycloalkyl, C 2 -C 6 alkenyl, C 6 -C 10 aryl or C 7 -C 11 aralkyl and R′ is hydrogen, C 1 -C 8 alkyl, C 6 -C 10 aryl or C 7 -C 11 aralkyl, the substituents R and R′ that are other than hydrogen being unsubstituted or substituted by halogen, hydroxyl, amino, C 1 -C 4 alkylamino, di-C 1 -C 4 alkoxy, carboxy or C 2 -C 5 alkoxycarbonyl; and the metal or metalloid is one from Group IA, IB, IIA, IIB, IA, IVA, VA or VII of the Periodic Table; and (B) at least one flame retardant component based on a nitrogen compound, and also the use thereof in synthetic polymers.

The invention relates to a novel flame retardant combination and to theuse thereof in synthetic, especially thermoplastic, polymers.

Metal salts of phosphonic acids, on their own or in combination withother components, are known as flame retardants for a large number ofthermoplastic polymers, for example from GB-A-2 211 850, EP-A-245 207,EP-A-343 109 and DE-A-3 833 977, wherein special emphasis is to be givento the salts of the methyl ester of methyl phosphonic acid.

Nitrogen-containing flame retardants, especially those based onmelamine, have been known for a long time and are, in some cases,commercially available. Some of those melamine derivatives also containphosphorus. Examples of publications relating to such flame retardantsare, inter alia, EP-A-782 599, EP-A-1 095 030, U.S. Pat. No. 4,010,137and U.S. Pat. No. 3,915,777.

Combinations of nitrogen-containing flame retardants with flameretardants based on phosphorus compounds are also known. In that respectsee, for example, DE-A-197 34 437, DE-A-197 37 727, WO-A-97/39053,EP-A-1 070 754, EP-A-6568 and DE-A-196 14 424.

There is a continuing need for flame retardants that have improvedproperties and that can be used in various plastics. In particular,increased safety and environmental requirements mean that hitherto knownflame retardants are no longer capable of satisfying all demands.

It has now been found that the combined use of nitrogen-containing flameretardants, especially those based on melamine, with salts of alkyl- oraryl-phosphonic acids, delivers outstanding action in a number ofpolymers.

The invention accordingly relates to a flame retardant comprisingA. at least one metal or metalloid salt of a phosphonic acid of formulaI

wherein R is hydrogen, C₁-C₁₈alkyl, C₅-C₆cycloalkyl, C₂-C₆alkenyl,C₆-C₁₀aryl or C₇-C₁₁aralkyl and R′ is hydrogen, C₁-C₈alkyl, C₆-C₁₀arylor C₇-C₁₁aralkyl, the substituents R and R′ that are other than hydrogenbeing unsubstituted or substituted by halogen, hydroxyl, amino,C₁-C₄alkylamino, di-C₁-C₄alkylamino, C₁-C₄alkoxy, carboxy orC₂-C₅alkoxycarbonyl; and the metal or metalloid is from Group IA, IB,IIA, IIB, IIIA, IVA, VA or VIII of the Periodic Table; andB. at least one nitrogen-containing flame retardant component offormulae III to VIIIa

whereinR⁴ to R⁶ are each independently of the others hydrogen, C₁-C₈alkyl,C₅-C₆cycloalkyl or C₁-C₄alkyl-C₅-C₆cycloalkyl, each unsubstituted orsubstituted by a hydroxy or C₁-C₄-hydroxyalkyl group; C₂-C₈alkenyl,C₁-C8-alkoxy, -acyl, -acyloxy, C₅-C₁₂aryl, —O—R² or —N(R²)R³, and R² andR³ are hydrogen, C₁-C₄alkyl, C₅-C₆cycloalkyl, C₂-C₈alkenyl,C₁-C₄hydroxyalkyl or C₆-C₁₂aryl, with the proviso that R⁴ to R⁶ are notsimultaneously hydrogen and also, in formula III, not simultaneously—NH₂, and in formula VII at least one group is present which is capableof adding a proton,R⁷ to R¹¹ each independently of the others have the same possiblemeanings as R⁴ to R⁶ with the exception of —N(R²)R³, X is the anion of aprotonic acid, x is the number of protons transferred from the latter tothe triazine compound and y is the number of protons abstracted from theprotonic acid;or ammonium polyphosphate, a melamine ammonium phosphate, a melamineammonium polyphosphate, melamine ammonium pyrophosphate, a condensationproduct of melamine or/and a reaction product of melamine withphosphoric acid or/and a reaction product of a condensation product ofmelamine with phosphoric acid or mixtures thereof.

In formula I, alkyl groups R and R′ contain preferably from 1 to 8, forexample from 1 to 6, especially from 1 to 4, carbon atoms. Aryl groupsare preferably naphthyl and especially phenyl. Aralkyl is especiallyphenyl-C₁-C₄alkyl or naphthylmethyl, more especially benzyl orphenylethyl. When such groups R or R′ are further substituted, theycarry especially from 1 to 3 of the substituents mentioned.

Special preference is given to R being C₁-C₃alkyl and R′ being hydrogenor methyl. Examples of the metal are Na, K, Mg, Ca, Ba, Zn, B, Al, Cu,Fe, Sn or Sb, especially Mg or Al, more especially the latter.

The salts may be present as simple ionic compounds comprising the anionsof phosphonic acid and the cations of the metal or metalloid.

When R′ is hydrogen and the metal or metalloid has a valency of morethan one, the salt can have a polymeric structure according to thefollowing formula II

wherein R is as defined hereinbefore, M is a metal or metalloid, n has avalue corresponding to the valency of M minus 1, m is a number from 2 to100 and wherein each group

is bonded only to M atoms.

As examples of phosphonic acid salts that may be used in accordance withthe invention there may be mentioned:

The phosphonic acid salts according to the definition either are knownor can be prepared in accordance with methods known per se. Examples ofsuch methods are to be found in, inter alia, EP-A-245 207, pages 4 and 5to 7 (Examples 1 to 14).

The symbol X in formula VII denotes, for example, an anion of phosphoricacid, polyphosphoric acid (linear or branched), pyrophosphoric acid,phosphinic acid, phosphonic acid or boric acid.

R⁴ to R⁶ are, for example, each independently of the others, hydrogen,C₁-C₄alkyl, cyclopentyl, cyclohexyl, methylcyclohexyl,C₁-C₄hydroxyalkyl, C₂-C₆alkenyl, C₁-C₄alkoxy, phenyl which isunsubstituted or substituted by from 1 to 3 methyl or methoxy groupsor/and by halogen atoms, —OR² or —NR²R³, wherein R² and R³ are eachindependently of the other hydrogen, C₁-C₄alkyl, C₁-C₄hydroxyalkyl,cycloalkyl, methylcyclohexyl or phenyl which is unsubstituted orsubstituted by from 1 to 3 methyl or methoxy groups or/and halogenatoms. In formula III, preference is given to at least one of R² and R³being other than hydrogen.

For R⁷ to R¹¹ the same preferences as for R⁴ to R⁶ also apply byanalogy.

As component B there are advantageously used compounds of formulae IV,V, VI, VII, VIII and VIIIa and also the melamine compounds specificallymentioned, especially the compounds of formulae VII, VIIIa and also themelamine compounds specifically mentioned.

Preferred nitrogen compounds (component B) are, for example,benzoguanamine (formula III, R⁴=phenyl, R⁵═R⁶═—NH₂), tris(hydroxyethyl)isocyanurate (formula IV, R⁷═R⁸═R⁹═—CH₂—CH₂—OH), allantoin (formula V,R⁷═R⁸═R⁹═R¹⁰═R¹¹═H), glycoluril (formula VI, R⁷═R⁸═R⁹═R¹⁰═H) and alsomelamine phosphate, dimelamine phosphate and melamine pyrophosphate,melamine polyphosphate, melamine borate (all of formula VII type), ureacyanurate (formula VIII type), melamine cyanurate (formula VIIIa type),and also melam or melem phosphate, melam or melem polyphosphate,ammonium polyphosphate, melamine ammonium phosphate, pyrophosphate orpolyphosphate.

The compounds used as component B are known or can be obtained by knowncustomary methods. Some of them are commercially available.

Special emphasis should be given to flame retardants according to theinvention wherein, in component A, R is C₁-C₄alkyl which isunsubstituted or substituted by from 1 to 3 halogen atoms or/andhydroxyl groups and R′ is hydrogen or C₁-C₄alkyl, especially thosewherein R is C₁-C₃alkyl and R′ is hydrogen or C₁-C₃alkyl, and moreespecially those wherein R and R′ are each methyl and the metal is Al.

Advantageously, component B in the flame retardants is benzoguanamine,tris(hydroxyethyl) isocyanurate, allantoin, glycoluril, melaminecyanurate, melamine phosphate, dimelamine phosphate, melaminepyrophosphate, urea cyanurate, melamine polyphosphate, melamine borate,ammonium polyphosphate, melamine ammonium polyphosphate or melamineammonium pyrophosphate, preferably a condensation product of melaminefrom the series melem, melam, melon and/or a higher condensed compoundor a reaction product of melamine with phosphoric acid and/or a reactionproduct of condensation products of melamine with phosphoric acid or amixture thereof. Special emphasis should be given to: dimelaminepyrophosphate, melamine polyphosphate, melem polyphosphate, melampolyphosphate, and/or a mixed polysalt of such a type, more especiallymelamine polyphosphate.

The ratio of components A and B may vary within wide limits and isdependent upon the intended use. Examples of ratios A:B are from 5:95 to95:5, e.g. from 10:90 to 90:10, preferably from 20:80 to 80:20,especially from 30:70 to 70:30 and from 40:60 to 60:40.

Both component A and component B may comprise one or more compounds offormula I or/and II or of formulae III to VIIIa or the melaminecompounds specifically mentioned, mixtures of compounds of differentformulae being possible.

The flame retardants according to the invention are outstandinglysuitable for imparting flame-retarding properties to synthetic polymers,especially thermoplastics.

Examples of such synthetic polymers are:

1. Polymers of mono- and di-olefins, for example polypropylene,polyisobutylene, polybutene-1, poly-4-methylpentene-1,polyvinylcyclohexane, polyisoprene or polybutadiene and alsopolymerisates of cyclo-olefins, for example of cyclopentene ornorbornene; and also polyethylene (which may optionally be crosslinked),for example high density polyethylene (HDPE), high density polyethyleneof high molecular weight (HDPE-HMW), high density polyethylene ofultra-high molecular weight (HDPE-UHMW), medium density polyethylene(MDPE), low density polyethylene (LDPE), and linear low densitypolyethylene (LLDPE), (VLDPE) and (ULDPE).

Polyolefins, that is to say polymers of mono-olefins, as mentioned byway of example in the preceding paragraph, especially polyethylene andpolypropylene, can be prepared by various processes, especially by thefollowing methods:

-   -   a) by free radical polymerisation (usually at high pressure and        high temperature);    -   b) by means of a catalyst, the catalyst usually containing one        or more metals of group IVb, Vb, VIb or VIII. Those metals        generally have one or more ligands, such as oxides, halides,        alcoholates, esters, ethers, amines, alkyls, alkenyls and/or        aryls, which may be either π- or σ-coordinated. Such metal        complexes may be free or fixed to carriers, for example to        activated magnesium chloride, titanium(III) chloride, aluminium        oxide or silicon oxide. Such catalysts may be soluble or        insoluble in the polymerisation medium. The catalysts can be        active as such in the polymerisation or further activators may        be used, for example metal alkyls, metal hydrides, metal alkyl        halides, metal alkyl oxides or metal alkyl oxanes, the metals        being elements of group(s) Ia, IIa and/or IIIa. The activators        may have been modified, for example, with further ester, ether,        amine or silyl ether groups. Such catalyst systems are usually        referred to as Phillips, Standard Oil Indiana, Ziegler (-Natta),        TNZ (DuPont), metallocene or Single Site Catalysts (SSC).        2. Mixtures of the polymers mentioned under 1), for example        mixtures of polypropylene with polyisobutylene, polypropylene        with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of        different types of polyethylene (for example LDPE/HDPE).        3. Copolymers of mono- and di-olefins with one another or with        other vinyl monomers, for example ethylene/propylene copolymers,        linear low density polyethylene (LLDPE) and mixtures thereof        with low density polyethylene (LDPE), propylene/butene-1        copolymers, propylene/isobutylene copolymers, ethylene/butene-1        copolymers, ethylene/hexene copolymers, ethylene/methylpentene        copolymers, ethylene/heptene copolymers, ethylene/octene        copolymers, ethylene/vinylcyclohexane copolymers,        ethylene/cyclo-olefin copolymers, for example        ethylene/norbornene (COC), ethylene/1-olefin copolymers wherein        the 1-olefin is prepared in situ, propylene/butadiene        copolymers, isobutylenefisoprene copolymers, ethylene/vinyl        cyclohexene coplymers, ethylene/alkyl acrylate copolymers,        ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate        copolymers, ethylene/acrylic acid copolymers and salts thereof        (ionomers), and also terpolymers of ethylene with propylene and        a diene, such as hexadiene, dicyclopentadiene or        ethylidenenorbornene; and also mixtures of such copolymers with        one another or with polymers mentioned under 1), for example        polypropylene-ethylene/propylene copolymers, LDPE-ethylene/vinyl        acetate copolymers, LDPE-ethylene/acrylic acid copolymers,        LLDPE-ethylenelvinyl acetate copolymers, LLDPE-ethylene/acrylic        acid copolymers and alternately or randomly structured        polyalkylene-carbon monoxide copolymers and mixtures thereof        with other polymers, for example polyamides.        4. Polystyrene, poly(p-methylstyrene), poly(α-methylstyrene).        5. Aromatic homopolymers and copolymers derived from        vinyl-aromatic monomers, for example styrene, α-methylstyrene,        all isomers of vinyltoluene, for example p-vinyltoluene, all        isomers of ethylstyrene, propylstyrene, vinylbiphenyl,        vinyinaphthalene, vinylanthracene and mixtures thereof;        homopolymers and copolymers can have a syndiotactic, isotactic,        hemi-isotactic or atactic stereo structure; preference is given        to atactic polymers. Also included are stereoblock polymers.        6a. Copolymers including the already mentioned vinyl-aromatic        monomers and comonomers selected from ethylene, propylene,        dienes, nitriles, acids, maleic anhydrides, maleic acid amides,        vinyl acetate, vinyl chloride and acrylic acid derivatives and        mixtures thereof, for example styrene/butadiene,        styrene/acrylonitrile, styrene/ethylene (interpolymers),        styrene/alkyl methacrylate, styrene/butadiene/alkyl acrylate and        methacrylate, styrene/maleic anhydride,        styrene/acrylonitrile/methyl acrylate; high-impact-strength        mixtures consisting of styrene copolymers and another polymer,        for example a polyacrylate, a diene polymer or an        ethylenelpropylene/diene terpolymer; and also block copolymers        of styrene, for example styrene/butadiene/styrene,        styrene/isoprene/styrene, styrene/ethylene-butylene/styrene or        styrene/ethylene-propylene/styrene.        6b. Hydrogenated aromatic polymers prepared by hydrogenation of        the polymers mentioned under 6.), especially        polycyclohexylethylene (PCHE), often also referred to as        polyvinylcyclohexane (PVCH), which is prepared by hydrogenation        of atactic polystyrene.        6c. Hydrogenated aromatic polymers prepared by hydrogenation of        the polymers mentioned under 6a.).        Homopolymers and copolymers can have a syndiotactic, isotactic,        hemi-isotactic or atactic stereo structure; preference is given        to atactic polymers. Also included are stereoblock polymers.        7. Graft copolymers of vinyl-aromatic monomers, for example        styrene on polybutadiene, styrene on polybutadiene/styrene or        polybutadiene/acrylonitrile copolymers, styrene and        acrylonitrile (or methacrylonitrile) on polybutadiene; styrene,        acrylonitrile and methyl methacrylate on polybutadiene; styrene        and maleic anhydride on polybutadiene; styrene, acrylonitrile        and maleic anhydride or maleic acid imide on polybutadiene;        styrene and maleic acid imide on polybutadiene, styrene and        alkyl acrylates or alkyl methacrylates on polybutadiene, styrene        and acrylonitrile on ethylene/propylene/diene terpolymers,        styrene and acrylonitrile on polyalkyl acrylates or polyalkyl        methacrylates, styrene and acrylonitrile on acrylate/butadiene        copolymers, and mixtures thereof with the copolymers mentioned        under 6), such as those known, for example, as so-called ABS,        MBS, ASA or AES polymers.        8. Halogen-containing polymers, for example polychloroprene,        chlorinated rubber, chlorinated and brominated copolymer of        isobutylene/isoprene (halobutyl rubber), chlorinated or        chlorosulfonated polyethylene, copolymers of ethylene and        chlorinated ethylene, epichlorohydrin homo- and co-polymers,        especially polymers of halogen-containing vinyl compounds, for        example polyvinyl chloride, polyvinylidene chloride, polyvinyl        fluoride, polyvinylidene fluoride; and copolymers thereof, such        as vinyl chloride/vinylidene chloride, vinyl chloride/vinyl        acetate or vinylidene chloride/vinyl acetate.        9. Polymers derived from α,β-unsaturated acids and derivatives        thereof, such as polyacrylates and polymethacrylates, or        polymethyl methacrylates, polyacrylamides and polyacrylonitriles        impact-resistant-modified with butyl acrylate.        10. Copolymers of the monomers mentioned under 9) with one        another or with other unsaturated monomers, for example        acrylonitrile/butadiene copolymers, acrylonitrile/alkyl acrylate        copolymers, acrylonitrile/alkoxyalkyl acrylate copolymers,        acrylonitrile/vinyl halide copolymers or acrylonitrile/alkyl        methacrylate/butadiene terpolymers.        11. Polymers derived from unsaturated alcohols and amines or        their acyl derivatives or acetals, such as polyvinyl alcohol,        polyvinyl acetate, stearate, benzoate or maleate,        polyvinylbutyral, polyallyl phthalate, polyallylmelamine; and        the copolymers thereof with olefins mentioned in Point 1.        12. Homo- and co-polymers of cyclic ethers, such as polyalkylene        glycols, polyethylene oxide, polypropylene oxide or copolymers        thereof with bisglycidyl ethers.        13. Polyacetals, such as polyoxymethylene, and also those        polyoxymethylenes which contain comonomers, for example ethylene        oxide; polyacetals modified with thermoplastic polyurethanes,        acrylates or MBS.        14. Polyphenylene oxides and sulfides and mixtures thereof with        styrene polymers or polyamides.        15. Polyamides and copolyamides derived from diamines and        dicarboxylic acids and/or from aminocarboxylic acids or the        corresponding lactams, such as polyamide 4, polyamide 6,        polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11,        polyamide 12, aromatic polyamides derived from m-xylene, diamine        and adipic acid; polyamide 6/I (polyhexamethylene        isophthalimide, MXD (m-xylylenediamine); polyamides prepared        from hexamethylenediamine and iso- and/or tere-phthalic acid and        optionally an elastomer as modifier, for example        poly-2,4,4-trimethylhexamethylene terephthalamide or        poly-m-phenylene isophthalamide. Block copolymers of the        above-mentioned polyamides with polyolefins, olefin copolymers,        ionomers or chemically bonded or grafted elastomers; or with        polyethers, for example with polyethylene glycol, polypropylene        glycol or polytetramethylene glycol. Also polyamides or        copolyamides modified with EPDM or ABS; and polyamides condensed        during processing (“RIM polyamide systems”).        Examples of polyamides and copolyamides that can be used are        derived from, inter alia, ε-caprolactam, adipic acid, sebacic        acid, dodecanoic acid, isophthalic acid, terephthalic acid,        hexamethylenediamine, tetramethylenediamine,        2-methyl-pentamethylenediamine,        2,2,4-trimethylhexamethylenediamine,        2,4,4-trimethylhexamethylenediamine, m-xylylenediamine or        bis(3-methyl-4-aminocyclohexyl)methane;        and also semi-aromatic polyamides such as polyamide 66/6I, for        example consisting of 70-95% polyamide 6/6 and 5-30% polyamide        6/I; and also tricopolymers in which some of the polyamide 6/6        has been replaced, for example consisting of 60-89% polyamide        6/6, 5-30% polyamide 6/I and 1-10% of another aliphatic        polyamide; the latter may consist of, for example, polyamide 6,        polyamide 11, polyamide 12 or polyamide 6/12 units. Such        tricopolymers may accordingly be designated polyamide 66/6I/6,        polyamide 66/6I/11, polyamide 66/6I/12, polyamide 66/6I/610 or        polyamide 66/6I/612.        16. Polyureas, polyimides, polyamide imides, polyether imides,        polyester imides, polyhydantoins and polybenzimidazoles.        17. Polyesters derived from dicarboxylic acids and dialcohols        and/or from hydroxycarboxylic acids or the corresponding        lactones, such as polyethylene terephthalate, polypropylene        terephthalate, polybutylene terephthalate,        poly-1,4-dimethylolcyclohexane terephthalate, polyalkylene        naphthalate (PAN) and polyhydroxybenzoates, and also block        polyether esters derived from polyethers with hydroxyl terminal        groups; and also polyesters modified with polycarbonates or MBS.        18. Polycarbonates and polyester carbonates.        19. Polyketones        20. Polysulfones, polyether sulfones and polyether ketones.        21. Mixtures (polyblends) of the afore-mentioned polymers, for        example PP/EPDM, polyamide/EPDM or ABS, PVC/EVA, PVC/ABS,        PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE,        PVC/acrylates, POM/thermoplastic PUR, PC/thermoplastic PUR,        POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA 6.6 and copolymers,        PA/HDPE, PA/PP, PA/PPO, PBT/PC/ABS or PBT/PET/PC.

The present invention accordingly relates also to the use of the flameretardants according to the invention in imparting flame-resistantproperties to synthetic polymers, especially to thermoplastics, and alsoto a method of imparting flame-resistant properties to syntheticpolymers, wherein at least one flame retardant according to theinvention is incorporated in the synthetic polymers or is applied totheir surface.

The invention relates also to a composition comprising

a) a synthetic polymer and

b) a flame retardant according to the invention, the synthetic polymerpreferably being a thermoplastic polymer.

Preference is given to compositions wherein the thermoplastic polymer ishigh-impact polystyrene (HIPS), expandable polystyrene (EPS), expandedpolystyrene (XPS), polyphenylene ether (PPE), polyamide, polyester,polycarbonate (PC) or a polymer blend of the type ABS(acrylonitrile-butadiene-styrene) or PC/ABS(polycarbonate/acrylonitrile-butadiene-styrene) or PPE/HIPS(polyphenylene ether/high-impact polystyrene), especially a polyamide,polyester or a PPE/HIPS blend.

Special preference is given to polymer compositions according to theinvention that comprise a filler or a reinforcing agent, especiallyglass-fibre-reinforced polymers, e.g. glass-fibre-reinforced polyamide.

Preparation of the compositions according to the invention may becarried out either by adding or applying the flame retardants consistingof components A and B according to the invention or, however, by addingor applying the individual components A and B separately.

Preference is given to the use of components A and B, each independentlyof the other, in a concentration of from 1 to 30% by weight, for examplefrom 3 to 20% by weight, preferably from 3 to 15% by weight, based onthe plastics moulding material.

The compositions according to the invention contain the flame retardantconsisting of components A and B in an amount of, for example, from 1 to50% by weight, preferably from 3 to 40% by weight, especially from 3 to30% by weight or from 8 to 30% by weight, based on the composition.

The flame-retarding components A and B may be incorporated in thepolymers, for example by pre-mixing all the constituents in the form ofpowder and/or granules in a mixer and then homogenising in the polymermelt in a compounding unit (inter alia, a twin-screw extruder). The meltis usually drawn off in the form of an extrudate, cooled and granulated.Components A and B may also be directly introduced separately into thecompounding unit by means of a feed unit.

It is likewise possible for the flame-retarding components A and B to beadmixed with finished polymer granules or powder and the mixtureimmediately processed into moulded articles using an injection-mouldingmachine. In the case of polyesters, for example, the flame-retardingadditives A and B may also already be added to the polyester materialduring polycondensation.

The polymer compositions according to the invention may be in the formof moulding materials, films, fibres and other moulded articles or inthe form of surface-coating compositions or may be further processedinto such forms.

It can be advantageous for the flame retardants according to theinvention to be processed into a stable product form before addition tothe polymer(s) in question to produce the polymer compositions accordingto the invention. This may serve the purpose, on the one hand, of bettermeterability and better industrial hygiene (e.g. freedom from dust) and,on the other hand, of a stable form for marketing. Preferred productforms of the latter kind are, for example, granules and agglomerates.The former can be obtained, for example, by extruding mixtures from anextruder and granulating the extrudate. Alternatively, the mixture canbe heated to above the melting point and the melt solidified byconventional methods (e.g. dripping onto a cooling belt or into a liquidsuch as water or spraying into air). In such methods the flame retardantmixture according to the invention may be processed as such or afteraddition of a carrier or of another adjuvant, for example a wax,plasticiser etc.. Examples of the methods mentioned can be found in, forexample, EP-A-392 392 and EP-A-565 184.

To produce agglomerates, for example, an organic adjuvant, for example apolyvinyl alcohol, polyvinylpyrrolidone or polyvinylcaprolactam, isadded to a mixture of the flame retardant according to the invention andthen spray-dried. By that means, a free-flowing, dust-free agglomerateis obtained. It can be obtained, for example, analogously to the methoddescribed in WO-A-03/035736.

The flame-resistant polymer compositions are suitable, inter alia, forthe production of moulded articles, films, threads and fibres, forexample by injection-moulding, extrusion or compression-moulding.

In addition to the flame-retarding combination of A and B according tothe invention, further customary components, for example fillers andreinforcing agents such as glass fibres, glass beads or minerals such aschalk, may be added to the polymer compositions. In addition, otheradditives such as antioxidants, light stabilisers, lubricants,colorants, nucleating agents or antistatics may be included.

Examples of further additives optionally present in the compositionsaccording to the invention are:

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, linear nonylphenols ornonylphenols branched in the side-chain, e.g.2,6-dinonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)-phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)-phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)-phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctyl-thiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-didodecylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxy-phenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octa-decyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

1.4. Tocopherols, for example α-tocopherol, β-tocopherol, γ-tocopherol,δ-tocopherol and mixtures thereof (Vitamin E).

1.5. Hydroxylated thiodiphenyl ethers, for example2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis(3,6-di-sec-amylphenol),4,4′-bis(2,6-dimethyl-4-hydroxyphenyl) disulfide.

1.6. Alkylidene bisphenols, for example2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)-phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methylphenyl)-dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate, 1,1-bis(3, 5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecyl-mercaptobutane,1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7. O—, N— and S-benzyl compounds, for example3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether,octadecyl-4-hydroxy-3,5-dimethylbenzyl mercaptoacetate,tridecyl4-hydroxy-3,5-di-tert-butylbenzyl mercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide,isooctyl-3,5-di-tert-butyl-4-hydroxybenzyl mercaptoacetate.

1.8. Hydroxybenzylated malonates, for example dioctadecyl2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)malonate, dioctadecyl2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate,didodecylmercaptoethyl2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,di-[4-(1,1,3,3-tetramethylbutyl)phenyl]2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Hydroxybenzyl aromatic compounds, for example1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetra-methylbenzene,2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine compounds, for example2,4-bisoctylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl4-hydroxybenzyl) isocyanurate.

1.11. Benzylphosphonates, for example dimethyl2,5-di-tert-butyl-4-hydroxybenzyl-phosphonate, diethyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl5-tert-butyl-4-hydroxy-3-methylbenzyl-phosphonate, calcium salt of3,5-di-tert-butyl-4-hydroxybenzyl-phosphonic acid monoethyl ester.

1.12. Acylaminophenols, for example 4-hydroxylauric acid anilide,4-hydroxystearic acid anilide,N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamic acid octyl ester.

1.13. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid withmono- or poly-hydric alcohols, for example with methanol, ethanol,n-octanol, isooctanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxalic aciddiamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or poly-hydric alcohols, for example with methanol, ethanol,n-octanol, isooctanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxalic aciddiamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane;3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

1.15. Esters of β-(3,5-dicyclohexyl4-hydroxyphenyl)propionic acid withmono- or poly-hydric alcohols, for example with methanol, ethanol,octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxalic acid diamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexane-diol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Esters of 3,5-di-tert-butyl4-hydroxyphenylacetic acid with mono-or poly-hydric alcohols, for example with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxalic acid diamide,3-thiaundecanol, 3-thiapentadecanol, trimethyl-hexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of β-(3,5-di-tert-butyl4-hydroxyphenyl)propionic acid, forexampleN,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamide,N,N′-bis(3, 5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide),N,N′-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]-propionyloxy)ethyl]-oxamide(Naugard®XL-1 from Uniroyal).

1.18. Ascorbic acid (Vitamin C).

1.19. Amine-type antioxidants, for exampleN,N′-di-isopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine, N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-di(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethyl-butyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfonamido)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthyl-amine,N-phenyl-2-naphthylamine, octylated diphenylamine, for examplep,p′-di-tert-octyl-diphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, di(4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4′-diaminodiphenylmethane, 4,4′-diamino-diphenylmethane, N,N,N′,N′-tetramethyl-4,4′-diaminodiphenyl methane,1,2-di[(2-methylphenyl)amino]ethane, 1,2-di(phenylamino)propane,(o-tolyl)-biguanide, di[4-(1′, 3′-dimethylbutyl)phenyl]amine,tert-octylated N-phenyl-1-naphthylamine, mixture of mono- anddi-alkylated tert-butyl-/tert-octyl-diphenylamines, mixture of mono- anddi-alkylated nonyl-diphenylamines, mixture of mono- and di-alkylateddodecyldiphenylamines, mixture of mono- and di-alkylatedisopropyl-/isohexyl-diphenylamines, mixtures of mono- and di-alkylatedtert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, mixture of mono- and di-alkylatedtert-butyl-/tert-octyl-phenothiazines, mixture of mono- and di-alkylatedtert-octylphenothiazines, N-allylphenothiazine, N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis(2,2,6,6-tetramethylpiperid-4-yl)-hexamethylenediamine,bis(2,2,6,6-tetramethylpiperid-4-yl) sebacate,2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

2. UV Absorbers and Light Stabilisers

2.1. 2-(2′-Hydroxyphenyl)-benzotriazoles, for example2-(2′-hydroxy-5′-methylphenyl)-benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)-benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)-phenyl)-benzotriazole,2-(3′, 5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)-benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)-benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxypheny)-benzotriazole,2-(3′,5′-bis(α,α-dimethylbenzyl)-2′-hydroxyphenyl)-benzotriazole,2-(3′-tert-butyl-21-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)-phenyl-benzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-yl-phenol];transesterification product of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-benzotriazolewith polyethylene glycol 300;

[R—CH₂CH₂—COO—CH₂CH₂—]₂ whereinR=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-yl-phenyl;2-[2′-hydroxy-3′-(α,α-dimethylbenzyl)-5′-(1,1,3,3-tetramethylbutyl)-phenyl]-benzotriazole;2-[2′-hydroxy-3′-(1,1,3,3-tetramethylbutyl)-5′-(α,α-dimethylbenzyl)-phenyl]-benzotriazole.

2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxy or2′-hydroxy-4,4′-dimethoxy derivative.

2.3. Esters of unsubstituted or substituted benzoic acids, for example4-tert-butyl-phenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol,benzoylresorcinol, 3,5-di-tert-butyl-4-hydroxybenzoic acid2,4-di-tert-butylphenyl ester, 3,5di-tert-butyl-4-hydroxybenzoic acidhexadecyl ester, 3,5-di-tert-butyl-4-hydroxybenzoic acid octadecylester, 3,5-di-tert-butyl-4-hydroxybenzoic acid2-methyl-4,6-di-tert-butylphenyl ester.

2.4. Acrylates, for example α-cyano-β,β-diphenylacrylic acid ethyl esteror isooctyl ester, α-methoxycarbonylcinnamic acid methyl ester,α-cyano-β-methyl-p-methoxycinnamic acid methyl ester or butyl ester,α-methoxycarbonyl-p-methoxycinnamic acid methyl ester,N-(β-methoxycarbonyl-β-cyanovinyl)-2-methyl-indoline.

2.5. Nickel compounds, for example nickel complexes of2,2′-thio-bis[4-(1,1,3,3-tetra-methylbutyl)phenol], such as the 1:1 or1:2 complex, optionally with additional ligands, such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithio-carbamate, nickel salts of4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid monoalkyl esters, suchas of the methyl or ethyl ester, nickel complexes of ketoximes, such asof 2-hydroxy-4-methylphenylundecyl ketoxime, nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, optionally with additionalligands.

2.6. Sterically hindered amines, for examplebis(2,2,6,6-tetramethylpiperid-4-yl) sebacate,bis(2,2,6,6-tetramethylpiperid-4-yl) succinate,bis(1,2,2,6,6-pentamethylpiperid-4-yl) sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperid-4-yl) sebacate,n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonic acidbis(1,2,2,6,6-pentamethylpiperidyl) ester, condensation product of1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, linear or cyclic condensation products ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetraoate,1,1′-(1,2-ethane-diyl)bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyl-oxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate, linear or cycliccondensation products ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, condensation product of2-chloro-4,6-di(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, condensation product of2-chloro-4,6-di(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione,mixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, condensation product ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, condensation product of1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine and4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [136504-96-6]);condensation product of 1,6-diaminohexane and2,4,6-trichloro-1,3,5-triazine and also N,N-dibutylamine and4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [192268-64-7]);N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimide,N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimide,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4.5]decane,reaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza4-oxospiro-[4.5]decaneand epichlorohydrin,1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene,N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine,diester of 4-methoxymethylenemalonic acid with1,2,2,6,6-pentamethyl-4-hydroxypiperidine,poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane,reaction product of maleic anhydride α-olefin copolymer and2,2,6,6-tetramethyl-4-aminopiperidine or1,2,2,6,6-pentamethyl-4-aminopiperidine.

2.7. Oxalic acid diamides, for example 4,4′-dioctyloxy oxanilide,2,2′-diethoxy oxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butyl oxanilide,2,2′-didodecyloxy-5,5′-di-tert-butyl oxanilide, 2-ethoxy-2′-ethyloxanilide, N,N′-bis(3-dimethylaminopropyl) oxalamide,2-ethoxy-5-tert-butyl-2′-ethyl oxanilide and a mixture thereof with2-ethoxy-2′-ethyl-5,4′-di-tert-butyl oxanilide, mixtures of o- andp-methoxy- and also of o- and p-ethoxy-di-substituted oxanilides.

2.8. 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropyloxy)phenyl],4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-hexyloxy)phenyl4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazine,2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine,2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

3. Metal deactivators, for example N,N′-diphenyloxalic acid diamide,N-salicylal-N′-salicyloylhydrazine, N,N′-bis(salicyloyl)hydrazine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalic aciddihydrazide, oxanilide, isophthalic acid dihydrazide, sebacic acidbis-phenylhydrazide, N,N′-diacetyladipic acid dihydrazide,N,N′-bis-salicyloyloxalic acid dihydrazide,N,N′-bis-salicyloylthiopropionic acid dihydrazide.

4. Phosphites and phosphonites, e.g. triphenyl phosphite, diphenylalkylphosphites, phenyldialkyl phosphites, tris(nonylphenyl)phosphite,trilauryl phosphite, trioctadecyl phosphite, distearyl-pentaerythritoldiphosphite, tris(2,4-di-tert-butylphenyl)phosphite,diisodecylpentaerythritol diphosphite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,4-di-cumylphenyl)-pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,bis-isodecyloxy-pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene diphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenzo[d,g]-1,3,2-dioxaphosphocine,bis(2,4-di-tert-butyl-6-methylphenyl) methylphosphite,bis(2,4-di-tert-butyl-6-methylphenyl) ethylphosphite,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenzo[d,g]-1,3,2-dioxaphosphocine,2,2′,2″-nitrilo[triethyl-tris(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)-phosphite],2-ethylhexyl-(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite,5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphirane.

5. Hydroxylamines, for example N,N-dibenzylhydroxylamine,N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine,N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine,N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine,N-hexadecyl-N-octadecylhydroxylamine,N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine fromhydrogenated tallow fatty amines.

6. Nitrones, for example N-benzyl-alpha-phenylnitrone,N-ethyl-alpha-methylnitrone, N-octyl-alpha-heptylnitrone,N-lauryl-alpha-undecylnitrone, N-tetradecyl-alpha-tridecylnitrone,N-hexadecyl-alpha-pentadecyinitrone,N-octadecyl-alpha-heptadecyinitrone,N-hexadecyl-alpha-heptadecylnitrone,N-octadecyl-alpha-pentadecyinitrone,N-heptadecyl-alpha-hepta-decylnitrone,N-octadecyl-alpha-hexadecylnitrone, nitrones derived fromN,N-dialkyl-hydroxylamines prepared from hydrogenated tallow fattyamines.

7. Thiosynergistic compounds, for example thiodipropionic acid dilaurylester or thio-dipropionic acid distearyl ester.

8. Peroxide-destroying compounds, for example esters ofp-thio-dipropionic acid, for example the lauryl, stearyl, myristyl ortridecyl ester, mercaptobenzimidazole, the zinc salt of2-mercaptobenzimidazole, zinc dibutyldithiocarbamate,dioctadecyldisulfide, pentaerythritoltetrakis(β-dodecylmercapto)propionate.

9. Polyamide stabilisers, for example copper salts in combination withiodides and/or phosphorus compounds and salts of divalent manganese.

10. Basic co-stabilisers, for example melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes, alkali metal andalkaline earth metal salts of higher fatty acids, for example calciumstearate, zinc stearate, magnesium behenate, magnesium stearate, sodiumricinoleate, potassium palmitate, antimony pyrocatecholate or zincpyrocatecholate.

11. Nucleating agents, for example inorganic substances, e.g. talc,metal oxides, such as titanium dioxide or magnesium oxide, phosphates,carbonates or sulfates of preferably alkaline earth metals; organiccompounds, such as mono- or poly-carboxylic acids and their salts, e.g.4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodiumsuccinate or sodium benzoate; polymeric compounds, for example ioniccopolymerisates (“ionomers”). Special preference is given to1,3:2,4-bis(3′,4′-dimethylbenzylidene)sorbitol,1,3:2,4-di(paramethyldibenzylidene)sorbitol and1,3:2,4-di(benzylidene)sorbitol.

12. Fillers and reinforcing agents, for example calcium carbonate,silicates, glass fibres, glass beads, talc, kaolin, mica, bariumsulfate, metal oxides and hydroxides, carbon black, graphite, woodpowders, and powders and fibres of other natural products, syntheticfibres.

13. Other additives, for example plasticisers, lubricants, emulsifiers,pigments, rheology additives, catalysts, flow improvers, opticalbrighteners, antistatics, blowing agents.

14. Benzofuranones and indolinones, for example as described in U.S.Pat. No. 4,325,863; U.S. Pat. No. 4,338,244; U.S. Pat. No. 5,175,312,U.S. Pat. No. 5,216,052; U.S. Pat. No. 5,252,643; DE-A-4 316 611; DE-A4316 622; DE-A-4 316 876; EP-A-0 589 839 or EP-A-0 591 102, or3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-one,5,7-di-tert-butyl-3-[4-(2-stearoyl-oxyethoxy)phenyl]benzofuran-2-one,3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)-benzofuran-2-one],5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one,3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxy-phenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(2,3-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one.

Polymer compositions according to the invention additionally comprise,for example, antioxidants, processing stabilisers, light stabilisers,metal deactivators, hydroxylamines, thiosynergistic compounds, coppersalts, nucleating agents, fillers, reinforcing agents, pigments and/orantistatics, especially phenolic or amine-type antioxidants,hydroxylamines, phosphites, phosphonites or/and benzofuranones and also,more especially, light stabilisers from the classes of UV absorbersor/and sterically hindered amines.

The flame retardants according to the invention and polymer compositionscomprising them may also comprise further flame retardants (componentC), for which any flame-retarding active ingredient from the classesknown hitherto is, in principle, suitable. Examples are antimonycompounds, for example antimony trioxide, antimony pentoxide or sodiumantimonate, especially in combination with halogen compounds; alkalineearth metal oxides, for example magnesium oxide or other metal oxidessuch as zinc oxide, aluminium oxide, argillaceous earth, silica, ironoxide or manganese oxide; metal hydroxides, for example magnesiumhydroxide or aluminium hydroxide; nanocomposites; mineral earths such asmontmorillonite or kaolin; modified mineral earths, for examplecomprising primary or quaternary ammonium compounds, melamine orphosphorus-containing compounds; silicon-containing compounds, forexample silicates, e.g. calcium silicate, organosilicon compounds(aliphatic or aromatic), for example silicones; titanates or zirconates;metal borates, for example zinc borate (hydrated or non-hydrated); othermetal compounds such as calcium sulfate, magnesium carbonate, molybdenumtrioxide; further phosphorus compounds, for example phosphates,phosphate esters, phosphonates, phosphinates, phosphines, phosphazenes,phosphine oxides or phosphites, amongst which preference is given tophosphates, phosphinates and phosphonates; sterically hinderedalkoxyamine compounds; and organohalogen compounds.

Sterically hindered alkoxyamine compounds correspond, for example, tothe formula

wherein G₁ and G₂ are each independently of the other C₁-C8alkyl ortogether are pentamethylene or hexamethylene, each being preferablyC₁-C₄alkyl, especially methyl,Z₁ and Z₂ are each methyl or Z₁ and Z₂ together are a bridging group,especially for completion of a 5- or 6-membered ring, preferably apiperidine ring, it being possible for the resulting N-heterocycle to beunsubstituted or substituted, for example by ester, ether, amide, amino,carboxy or urethane groups,E is alkoxy, alkenyloxy, cycloalkoxy, aralkoxy, aryloxy or O-T-(OH)_(b)and T is C₁-C18alkylene, C₅-C₁₈cycloalkylene, C₅-C₁₈cycloalkenylene, orC₁-C₄alkylene substituted by phenyl or by phenyl substituted by 1 or 2C₁-C₄alkyl groups, andb is 1, 2 or 3, with b not being greater than the number of carbon atomsin T and, when b is 2 or 3, each hydroxyl group being bonded to adifferent carbon atom.E is preferably C₁-C₁₈alkoxy, C₅-C₆cycloalkoxy, or C₁-C₁₈alkoxysubstituted by from 1 to 3 OH groups.

Examples of sterically hindered alkoxyamines of formula IX can be foundin U.S. Pat. No. 4,983,737, U.S. Pat. No. 5,047,489 and U.S. Pat. No.5,077,340, and also GB-A-2 373 507 (especially page 7, line 1 to page31, line 1; page 48, line 10 to page 52, third line from the bottom) andWO-A-03/050175 (especially page 11, penultimate line to page 37, lastline; page 54, line 9 to third last line; pages 61/62, compounds NOR1 toNOR12). The mentioned locations are to be considered as part of thepresent Application.

The organohalogen compounds optionally present in flame retardantsaccording to the invention may belong to a very great variety ofchemical classes. Examples thereof are halogenated aromatic compounds,for example halogenated benzenes, biphenyls; phenols, ethers or estersthereof; bisphenols, diphenyl oxides; aromatic carboxylic acids orpolyacids, anhydrides, amides or imides thereof; halogenatedcycloaliphatic or polycycloaliphatic compounds; and also halogenatedaliphatic compounds, for example halogenated paraffins, oligomers andpolymers, alkyl phosphates and alkyl isocyanurates. Examples of thementioned classes of compounds are known from the literature. In thatrespect, see, for example, U.S. Pat. No. 4,579,906 (e.g. column 3, lines30-41), U.S. Pat. No. 5,393,812 and also “Plastics Additives Handbook”,Ed. by H. Zweifel, 5^(th) Ed., Hanser Publ., Munich 2001, pages681-698).

Individual examples of such halogenated organic flame retardantcomponents are: chloroalkyl phosphate esters (Antiblaze® AB-100, Fyrol®FR-2), tris(2-chloroethyl) phosphate, polybrominated diphenyl oxide(DE-60F, Great Lakes Corp.), decabromodiphenyl oxide (DBDPO,Saytex®120E), tris[3-bromo-2,2-bis(bromomethyl)propyl] phosphate (PB370®, FMC Corp.), tris(2,3-dibromopropyl) phosphate,tris(2,3-dichloropropyl) phosphate, chlorendic acid, tetrachlorophthalicacid, tetrabromophthalic acid,bis(N,N′-hydroxyethyl)-tetrachloro-phenylenediamine, poly-β-chloroethyltriphosphonate mixture, bis(2,3-dibromopropyl ether) of bisphenol A(PE68), brominated epoxy resin, ethylene bis(tetrabromophthalimide)(Saytex®BT-93), bis(hexachlorocyclopentadiene)cyclooctane (DechloranePlus®), chlorinated paraffins, octabromodiphenyl ether,hexachlorocyclopentadiene derivatives, 1,2-bis(tribromophenoxy)ethane(FF680), tetrabromo-bisphenol A (Saytex® RB100), ethylenebis(dibromonorbornane-dicarboximide) (Saytex® BN-451),bis(hexachlorocyclopentadiene)-cyclooctane, polytetrafluoroethylene(Teflon® GC), tris(2,3-dibromopropyl) isocyanurate, ethylenebis(tetrabromophthalimide).

Among those, preference is given to organobromine flame retardants.

As examples of phosphorus-containing flame retardants there may bementioned, for example:

tetraphenylresorcinol diphosphite (Fyroflex® RDP), triphenyl phosphate,trioctyl phosphate, tricresyl phosphate,tetrakis(hydroxymethyl)phosphonium sulfide,diethyl-N,N-bis(2-hydroxyethyl)aminomethyl phosphonate, hydroxyalkylesters of phosphoric acids, ammonium polyphosphate (APP) or (Hostaflam®AP750), resorcinol diphosphate oligomer (RDP), phosphazene flameretardants and ethylenediamine diphosphate (EDAP).

The flame retardant component C from the class of phosphorus-containingflame retardants is advantageously a salt of melamine, or a condensationproduct thereof, with a phosphorus-containing acid, namely a monobasicphosphorus-containing acid, e.g. a phosphoric, phosphonic or,preferably, phosphinic acid having in each case only one acidequivalent; more especially, alkylphosphonic acid esters and,preferably, alkylphosphinic acid esters come into consideration. Thecationic component is, for example, melamine, melam, melem or a highercondensation product of melamine, preferably melamine or melam. Suchsalts and their preparation are described, for example, in EP-A-363 321and WO-A-01/57051.

Especially suitable as component C in flame retardants or flame-retardedpolymer compositions according to the invention are salts of organicphosphinic acids or diphosphinic acids, especially salts of formulae Xand XI

whereinR₁ and R₂, which are the same or different, are C₁-C₆alkyl, especiallyC₁-C₄alkyl, or C₆-C₁₀aryl;R₃ is C₁-C₁₀alkylene, C₆-C₁₀-arylene, -alkylarylene or -arylalkylene;M is magnesium, calcium, aluminium, zinc, melamine or a condensationproduct of melamine,m is 1, 2 or 3;n is 1 or 3 andx is 1 or 2.

M is preferably Zn, Al, melamine, melam or melem, especially Zn or Al.Aryl and arylene, alkylarylene and arylalkylene include, inter alia,phenyl, naphthyl, tolyl, xylyl, ethylphenyl, mesityl, propylphenyl ortert-butylphenyl and phenylene, naphthylene, methylphenyiene,ethylphenylene or tert-butylphenylene, methyinaphthylene,ethyinaphthylene, tert-butyl-naphthylene, phenylmethylene,phenylpropylene and the corresponding tolyl and xylyl analogues.

Special emphasis should accordingly be given to flame retardants andflame-retarded polymer compositions according to the invention thatcomprise as further flame retardant active ingredient (component C) atleast one such ingredient from the classes of antimony compounds, metaloxides or hydroxides, nanocomposites, mineral earths, modified mineralearths, organic or inorganic silicon compounds, titanates, zirconates,metal borates, phosphorus compounds, sterically hindered alkoxyaminecompounds and/or organohalogen compounds, for example those whereincomponent C is at least one from the classes antimony compounds,sterically hindered alkoxyamine compounds, phosphorus compounds or/andorganohalogen compounds. Especially suitable as component C are aphosphate, phosphate ester, phosphonate, phosphinate, phosphine,phosphine oxide, phosphite or/and phosphazene, more especially a metalsalt or melamine (including condensation products thereof) salt of aphosphinic acid of formulae X or/and XI.

The Examples that follow illustrate the invention further.

EXAMPLES 1-3

1. Components Used

Commercially available polymers (granules):

polyamide 6 (PA 6):

®Akulon K122 (DSM Engineering Plastics).

polyamide 6.6 (PA 6.6):

®Akulon S222 (DSM Engineering Plastics).

Glass fibres: standard glass fibres for polyamide, diameter 10 μm,length 4.5 mm.

Flame retardant components (in powder form):

Component A:

aluminium salt of methyl methyl phosphonic acid, hereinafter referred toas AIMMP. The compound was prepared in accordance with the procedure ofEP-B-245 205, Example 2 (page 5).

Component B:

Melapur®200 (melamine polyphosphate) from Ciba Specialty Chemicals Inc.,hereinafter referred to as M200.

Component C:

aluminium salt of diethyl phosphinic acid, hereinafter referred to asDEPAL.

2. Preparation, Processing and Testing of the Flame-Retarding PolymerCompositions:

The flame retardant components are mixed with the polymer granules inthe ratio indicated in the Table and, using a Haake kneader, arehomogenised at a temperature of 260° C. at 300 revolutions per minuteand then extruded. The polymer extrudate obtained is drawn off, cooledin air and then granulated.

After being sufficiently dried, the granules are processed, using aninjection moulding machine, at a mass temperature of 260° C. to formtest specimens having a thickness of 1.6 mm and, using the UL94 test(Underwriter Laboratories), they are tested for flame resistance andclassified. The results obtained are given in the following Table. TABLEExample 1 Example 2 Example 3 PA 6 50 50 PA 66 50 AIMMP 11 11 8.33 M20011 11 8.33 Glass fibres 28 28 25 DEPAL 8.33 Result of V0 V0 V0 UL94 test

The figures in the Table indicate parts by weight.

The results show that the flame retardant combinations according to theinvention impart outstanding flame resistance to the polymers tested (V0is the best flammability class according to the UL94 test).

1. A flame retardant comprising A) at least one metal or metalloid saltof a phosphonic acid of formula I

wherein R is hydrogen, C₁-C₁₈alkyl, C₅-C₆cycloalkyl, C₂-C₆alkenyl,C₈-C₁₀aryl or C₇-C₁₁aralkyl and R′ is hydrogen, C₁-C₈alkyl, C₆-C₁₀arylor C₇-C₁₁aralkyl, the substituents R and R′ that are other than hydrogenbeing unsubstituted or substituted by halogen, hydroxyl, amino,C₁-C₄alkylamino, di-C₁-C₄alkylamino, C₁-C₄alkoxy, carboxy orC₂-C₅alkoxycarbonyl; and the metal or metalloid is from Group IA, IB,IIA, IIB, IIIA, IVA, VA or VIII of the Periodic Table; and B) at leastone nitrogen-containing flame retardant component of formulae III toVIIIa

wherein R⁴ to R⁶ are each independently of the others hydrogen,C₁-C₈alkyl, C₅-C₆cycloalkyl or C₁-C₄alkyl-C₅-C₆cycloalkyl, eachunsubstituted or substituted by a hydroxy or a C₁-C₄-hydroxyalkyl group;C₂-C₈alkenyl, C₁-C₈-alkoxy, -acyl, -acyloxy, C₆-C₁₂aryl, —O—R or—N(R²)R³, and R² and R³ are hydrogen, C₁-C₄alkyl, C₅-C₆cycloalkyl,C₂-C₈alkenyl, C₁-C₄hydroxyalkyl or C₆-C₁₂aryl, with the proviso that R⁴to R⁶ are not simultaneously hydrogen and also, in formula III, notsimultaneously —NH₂, and in formula VII at least one group is presentwhich is capable of adding a proton, R⁷ to R¹¹ indicate the same groupsas R⁴ to R⁶ with the exception of the substituent —N(R²)R³, X is theanion of a protonic acid, x is the number of protons transferred fromthe latter to the triazine compound and y is the number of protonsabstracted from the protonic acid; or ammonium polyphosphate, a melamineammonium phosphate, melamine ammonium polyphosphate, melamine ammoniumpyrophosphate, a condensation product of melamine or/and a reactionproduct of melamine with phosphoric acid or/and a reaction product of acondensation product of melamine with phosphoric acid or a mixturethereof.
 2. A flame retardant according to claim 1, wherein R isC₁-C₄alkyl which is unsubsituted or substituted by from 1 to 3 halogenatoms or/and hydroxyl groups, and R′ is hydrogen or C₁-C₄alkyl.
 3. Aflame retardant according to claim 1, wherein the metal or metalloid isNa, K, Mg, Ca, Ba, Zn, B, Al, Cu, Fe, Sn or Sb.
 4. A flame retardantaccording to claim 1, wherein component B is at least one compound offormulae VII or/and VIIIa or/and ammonium polyphosphate, a melamineammonium polyphosphate, melamine ammonium pyrophosphate, a condensationproduct of melamine or/and a reaction product of melamine withphosphoric acid or/and a reaction product of a condensation product ofmelamine with phosphoric acid or/and a mixture thereof.
 5. A flameretardant according to claim 1, wherein component B is benzoguanamine,tris(hydroxyethyl) isocyanurate, allantoin, glycoluril, melaminecyanurate, melamine phosphate, dimelamine phosphate, melaminepyrophosphate, urea cyanurate, ammonium polyphosphate, melaminepolyphosphate, melamine borate, melamine ammonium polyphosphate ormelamine ammonium pyrophosphate.
 6. A flame retardant according to claim1, wherein component B is a condensation product of melamine from theseries melem, melam, melon and/or a higher condensed compound.
 7. Aflame retardant according to claim 1, wherein component B is a reactionproduct of melamine with phosphoric acid and/or a reaction product of acondensation product of melamine with phosphoric acid or a mixturethereof.
 8. A flame retardant according to claim 7, wherein component Bis dimelamine pyrophosphate, melamine polyphosphate, melempolyphosphate, melam polyphosphate and/or a mixed polysalt of that type.9. A flame retardant according to claim 1, comprising a furtherflame-retarding component C.
 10. A flame retardant according to claim 9,wherein component C is at least one flame-retarding active ingredientfrom the classes of antimony compounds, metal oxides or hydroxides,nanocomposites, mineral earths, modified mineral earths, organic orinorganic silicon compounds, titanates, zirconates, metal borates,phosphorus compounds, sterically hindered alkoxyamine compounds and/ororganohalogen compounds.
 11. A flame retardant according to claim 10,wherein component C is at least one flame-retarding active ingredientfrom the classes of antimony compounds, sterically hindered alkoxyaminecompounds, phosphorus compounds or/and organohalogen compounds.
 12. Aflame retardant according to claim 11, wherein component C is at leastone phosphate, phosphate ester, phosphonate, phosphinate, phosphine,phosphine oxide, phosphite or/and phosphazene.
 13. A flame retardantaccording to claim 11, wherein component C is a metal salt of analkylphosphinic acid ester or a salt of the latter with melamine or witha condensation product of melamine.
 14. A flame retardant according toclaim 13, wherein component C is at least one phosphonite of formulae Xor/and XI,

wherein R₁ and R₂, which are the same or different, are C₁-C₆alkyl,especially C₁-C₄alkyl, or C₈-C₁₀aryl; R₃ is C₁-C₁₀alkylene,C₈-C₁₀-arylene, -alkylarylene or -arylalkylene; M is magnesium, calcium,aluminium or zinc, melamine or a condensation product of melamine, m is1, 2 or 3; n is 1 or 3 and x is 1 or
 2. 15. A composition comprising a)a synthetic polymer and b) at least one flame retardant according toclaim
 1. 16. A composition according to claim 15, wherein component a)is a thermoplastic polymer.
 17. A composition according to claim 16,wherein the thermoplastic polymer is high-impact polystyrene (HIPS),expandable polystyrene (EPS), expanded polystyrene (XPS), polyphenyleneether (PPE), polyamide, polyester, polycarbonate or a polymer blend ofthe type ABS (acrylonitrile-butadiene-styrene) or PC/ABS(polycarbonate/acrylonitrile-butadiene-styrene) or PPE/HIPS(polyphenylene ether/high-impact polystyrene).
 18. A compositionaccording to claim 15, comprising a filler or a reinforcing agent.
 19. Acomposition according to claim 15, comprising an additional additive.20. A composition according to claim 19, comprising, as additionaladditive, an antioxidant, a processing stabiliser, a light stabiliser, ametal deactivator, a hydroxylamine, a thiosynergistic compound, a coppersalt, a nucleating agent, a filler, a reinforcing agent, a pigmentor/and an antistatic.
 21. A composition according to claim 20,comprising, as light stabiliser, a UV absorber or/and a light stabiliserfrom the class of sterically hindered amines.
 22. (canceled)
 23. Amethod of imparting flame-resistant properties to a synthetic polymer,wherein at least one flame retardant according to claim 1 isincorporated in the synthetic polymer or is applied to the surfacethereof.
 24. A composition comprising a) a synthetic polymer and b) atleast one flame retardant according to claim
 10. 25. A method ofimparting flame-resistant properties to a synthetic polymer, wherein atleast one flame retardant according to claim 10 is incorporated in thesynthetic polymer or is applied to the surface thereof.